Progress during the current reporting period has focused predominantly on start-up activities, including animal acquisition, conditioning, staff recruitment and training. Animals acquired for this project comprise 11 young adult rhesus monkeys, including 6 with MRI-guided and confirmed excitotoxic lesions restricted to the hippocampus. The remaining 5 subjects were acquired at the same time, and from the same source, serve as intact controls. Additional rhesus monkeys (n=26) were acquired to explore the effects of early rearing on neurocognitive aging. Ten are young adults and the remainder include a range of ages from late teens and older, when signatures of age-related cognitive decline emerge in rhesus monkeys. As infants, approximately half of the animals in both age groups were reared by adult females while the remainder were maintained in troops of other juveniles. This manipulation of early rearing conditions is known to influence subsequent physiological and psychological development, as measured by parameters that have been tracked into young adulthood. The novel question under investigation in the present project is whether the influence of early rearing persists throughout life, and predicts the cognitive and neurobiological outcome of normal aging.